usb: dfu: Migrate CONFIG_SYS_DFU_DATA_BUF_SIZE and CONFIG_SYS_DFU_MAX_FILE_SIZE to Kconfig

Currently the config options CONFIG_SYS_DFU_DATA_BUF_SIZE and
CONFIG_SYS_DFU_MAX_FILE_SIZE are being set in include/configs/<board>.h
files and also in <board_name>_defconfig files without a Kconfig option. It
is easier for users to set these configs in defconfig files than in config
header files as they are a part of the source code.

Add Kconfig symbols, and update the defconfigs by using tools/moveconfig.py
script.

Suggested-by: Pratyush Yadav <p.yadav@ti.com>
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Acked-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Acked-by: Matthias Brugger <mbrugger@suse.com>
Acked-by: Lukasz Majewski <lukma@denx.de>
diff --git a/configs/am65x_evm_r5_usbdfu_defconfig b/configs/am65x_evm_r5_usbdfu_defconfig
index 1616342..b45a6d2 100644
--- a/configs/am65x_evm_r5_usbdfu_defconfig
+++ b/configs/am65x_evm_r5_usbdfu_defconfig
@@ -65,6 +65,8 @@
 CONFIG_CLK=y
 CONFIG_SPL_CLK=y
 CONFIG_CLK_TI_SCI=y
+CONFIG_SYS_DFU_DATA_BUF_SIZE=0x5000
+CONFIG_SYS_DFU_MAX_FILE_SIZE=0x800000
 CONFIG_TI_SCI_PROTOCOL=y
 CONFIG_DA8XX_GPIO=y
 CONFIG_DM_I2C=y